Time controlled electric switch



Jan. 9, 1934. J. w. REDMOND 1,943,040

TIME CONTROLLED ELECTRIC swrrcn Filed Feb. 9, 1933 INVENTOR ATTORNEY Patented Jan. 9, 1934 TIME CONTROLLED ELECTRIC SWITCH James W. Redmond, Dayton, Ohio Application February 9, 1933. Serial No. 655,878

1 Claim.

My invention relates to new and useful improvements in time-controlled switches for electrical circuits.

It is the principal object of my invention to provide a time switch mechanism of simple structure that may be easily attached to a clock, by which it is operated.

It is another important object of my invention to provide with a switch mechanism a simple cam that may be cut to the proper profile by a novice and attached to a clock by which it is rotated to operate the switch mechanism.

Other important and incidental objects of my invention will be brought out in the following specification and claim subjoined thereto.

In the accompanying drawing illustrating a preferred embodiment of my invention, Figure 1 is a front view of an electrically operated clock equipped with my cam operated switch. Figure 2 is a back view of the clock illustrated at Figure 1 and showing the switch mechanism. Figure 3 is a sectional view taken on the line 33 of Figure 1 and showing the switch mechanism. Figure 4 is a partial front view, enlarged, showing a part of the cam and the cam follower. Figure 5 is a detail view of the mercury contacts closed with the cam follower in the up position. Figure 6 is a detail view of the mercury contact open or broken with the cam follower in the down position. Figure '7 is a detail view of the mercury contacts open with the cam follower in the up position. Figure 8 is a detail view of the mercury contacts closed with the cam follower in the down position and Figure 9 is a detail view of the method of attaching the cam disc to the hour hand of the clock mechanism.

Referring now to the accompanying drawing for a complete disclosure of. my invention, the numeral 1 indicates a conventional wall clock, having an outer casing 2, bezel 3, dial 4 and a synchronized electric motor operated clock mechanism 5 secured within the casing 2 and behind the dial 4. Although I have indicated an electrically-operated. mechanism, a spring-operated clock mechanism may also be used. (See Figures 1, 2 and 3).

My device comprises an offset bracket member 6 secured to the rear face of the dial by screws '7-'7 or other suitable means. Pivoted to the upper end of the bracket member 6 is a lateral arm 8 whose free end projects through a elongated slot 9 provided in the upper part of the dial 4 and substantially behind thenumeral 12.

. The free end of the arm 8 where it projects -through the slot 9 has a depending forked end 10 whose center portion is formed laterally to provide a curved cam follower 11 that bears upon the periphery of a cam disc 12 that is received between the forked ends 10. and 3) The cam disc 12 is preferably of a non-metallic material to eliminate alternating current hum, eddy currents and possible inaccuracies in the clocks operation. It is desirable to use a hard transparent material such as bakelite and at Figure 4 I have shown the cam disc 12 formed with twelve equally-spaced radial ribs or corrugations 13, each space between the adjacent ribs representing one hour. These ribs intersect near the periphery of the cam a circular rib or corrugation l4, denoting the bottom contour of the cam profile when the arm 8 is down and an outer circular rib or corrugation 14 denoting the outer profile of the cam when the arm 8 is in the extreme up position.

The cam disc 12 is applied to the clock by first removing the minute hand and the hour hand, the shaft being received by a center aperture 15 in the disc.

In order to provide a positive drive for the disc, I have provided a clip 16 of soft metal attached to the disc at one of the ribs 13 and having two outwardly projecting lugs 17, 1'7. When properly positioned on the dial, these lugs are bent over the hour hand, thus securing the disc. (See Figures 1, 3, 4 and 9).

Attached to the arm 8, behind the dial 4 is a spring bronze clip 18, between whose yieldable ends a conventional mercury contact unit 19 is mounted. This unit is glass enclosed and has sealed therein two contacts 20, 20, adapted to be electrically connected by a quantity of mercury 21, likewise sealed within the unit. When the unit is positioned with the lead end down as shown at Figure 5, the contacts will be shorted by the mercury, establishing an electrical circuit through the leads 22-22 connected with the contacts 20, 20. When the unit is inclined as shown at Figure 6 the mercury will move away from the contacts 20, 20 thus breaking the circuit.

The leads 22, 22 are connected with suitable terminals 23, 23 provided in the casing 2 for external connections. By reversing the position of the contact unit 19 in the clip 18 as shown at Figures 5 and 6 to the positions shown at Figures '7 and 8 the cycle of operations will be reversed.

With the simple cam disc that I employ, aided by the radial lines indicating time and the circular lines indicating the cam rise required, an unskilled person may readily form cams to suit vary- (See Figures 1, 2

a dial, a clock motor mounted behind said dial, hour and minute hands in front of said dial and a cam disc attached to said hour hand, an aperture formed in said dial, a pivoted arm behind said dial and extending through said aperture, cam follower means integral with said am and engaging said cam disc, contact means mounted on said arm, and means for making and breaking an electrical circuit through said contact means when the cam disc is rotated to move said pivoted arm.

JAMES W. REDMOND. 

